In his first-ever interview, the sole Australian survivor of the Waco siege has revealed to 60 Minutes what really took place during the 51-day stand-off, and why he believes crazed cult leader David Koresh will one day return to Earth as the son of God.

Bishop offers Mexico Aust help after quake

Australian Foreign Affairs Minister Julie Bishop says she is not aware of any Australian casualties from the catastrophic Mexican earthquake.

The death toll from the 7.1 magnitude tremblor that collapsed buildings in Mexico City and other areas has killed at least 225 people, including 30 schoolchildren.

"I have not been provided any such information, but of course our embassy in Mexico will be making all relevant enquiries of authorities," Ms Bishop, asked if she had been told of any Australians caught up in the earthquake, told reporters at the United Nations in New York on Wednesday.

"Our condolences are with the people of Mexico at this very sad and tragic time."

Ms Bishop said she had spoken to Mexican Foreign Affairs Minister Luis Videgaray Caso at the UN and offered to provide Australian support if Mexico required it.